1. Field of the Invention
The present invention relates, in general, to a method for controlling the purified water passage of a refrigerator with a water purifying filter and, more particularly, to a method for controlling the purified water passage of a refrigerator with a water purifying filter, which is capable of protecting the filter from being damaged.
2. Description of the Prior Art
As well known to those skilled in the art, some refrigerators have water purifying filters in their interiors, thereby supplying water purified by the filters to the outside of the refrigerators or producing ice using water purified by the filters.
FIG. 1 is a schematic perspective view showing the purified water passage of a conventional refrigerator with a water purifying filter. The conventional refrigerator comprises a refrigerator compartment 10 and a freezer compartment 20 that are partitioned by a barrier BR. A machine room 30 is positioned under the refrigerator compartment 10 and the freezer compartment 20.
A first valve 32 and a second valve 34 are mounted to the machine room 30. The first valve 32 serves to arrest water entering the interior of the refrigerator from a water pipe when an old filter is exchanged for a new one, and the second valve 34 serves to dispense purified water to the various portions of the refrigerator. The first and second valves 32 and 34 are solenoid valves, and are opened or closed by means of the attraction of a magnetic field that is generated when electric current is applied to the valves 32 and 34.
A water purifying filter 12 that is mounted to the refrigerator compartment 10 is connected to the first valve 32 via a connecting conduit D1. The filter 12 serves to purify water that has entered the refrigerator. A tank 14 is positioned on one side of the refrigerator compartment 10 and connected to the water purifying filter 12 and the second valve 34 respectively via a connecting conduit D2 and a connecting conduit D3. Water that has been purified in the filter 12 is stored in the tank 14 temporarily before it is supplied to a dispenser (will be described).
A refrigerator compartment door switch 16a is mounted to the refrigerator compartment door 16 and serves to inform a Central Processing Unit (CPU, will be described) whether the refrigerator compartment door is opened or not.
In the meantime, an ice-making unit 24 is mounted to the freezer compartment 20 and connected to the second valve 34 via a connecting conduit D4. An ice-making unit switch 24a that is positioned on one side of the ice-making unit 24 transmits a signal to the CPU when purified water is needed so as to make ice.
The dispenser 22 is mounted to one side of the freezer compartment 20 so as to supply the purified water to the outside of the refrigerator, and connected to the tank 14 via a connecting conduit D5. A dispenser switch 22a that is mounted to one side of the dispenser 22 transmits a signal to the CPU so as to supply the purified water to the outside of the refrigerator.
A freezer compartment door switch 26a is mounted to the freezer compartment door 16 and serves to inform the CPU whether the freezer compartment door 26 is opened or not.
With reference to FIGS. 2 and 3, a conventional method for controlling the purified water passage of the refrigerator with a water purifying filter will be described in detail.
Referring to FIG. 2, the CPU controls a first valve control 32a and a second valve control 34a in accordance with a preset control program in response to signals from the refrigerator compartment door switch 16a, the freezer compartment door switch 26a, the dispenser switch 22a and the ice-making unit switch 24a. That is, the first and second valve 32 and 34 are opened or closed in response to the signals of the refrigerator compartment door switch 16a, the freezer compartment door switch 26a, the dispenser switch 22a and the ice-making unit switch 24a.
FIG. 3 is a flowchart showing the conventional method for controlling the purified water passage of the refrigerator with a water purifying filter so as to control the opening of the first and second valves 32 and 34.
In accordance with the flowchart, the conventional purified water passage control method starts from the step of determining whether the refrigerator compartment door switch 16a is OFF (STEP 110). If the refrigerator compartment door switch 16a is OFF, that is, the refrigerator compartment door 16 is opened, the first and second switches 32 and 34 are closed (STEP 111). The reason why the first valve 32 is closed while the refrigerator compartment door 16 is opened is to prevent water from being supplied to the filter 12 when an old filter is exchanged for a new one.
On the other hand, if the refrigerator compartment door switch 16a is ON (NO in STEP 110), the step of determining whether the freezer compartment door switch 26a is OFF (STEP 112) is performed. If the freezer compartment door 26 is opened, and so the freezer compartment door switch 26a is OFF, the first valve 32 is opened and the second valve 34 is closed (STEP 113). That is, water that has passed through the opened first valve 32 is supplied to the filter 12 of the refrigerator compartment 10 via the connecting conduit D1. Additionally, water that is purified in the filter 12 is supplied to the second valve 34 of the machine room 30 via the connecting conduit D2. In such a case, since the second valve 34 is closed, purified water is not supplied to the ice-making unit 24 and the dispenser 22 while the refrigerator compartment door 26 is opened. The reason why the second valve 34 is closed while the freezer compartment door is opened is to prevent water from being leaked via the dispenser 22.
If the freezer compartment door switch 26a is ON (NO in STEP 112), the step of determining whether the dispenser switch 22a and the ice-making unit switch 24a are OFF (STEP 114) is performed. If the dispenser switch 22a and the ice-making unit switch 24a are OFF, the first valve 32 is opened and the second valve 34 is closed (STEP 116). As a result, since the first valve 32 is opened when water supply to the dispenser 22 and the ice-making unit 24 is not needed while the freezer compartment door 26 is closed, water is supplied to the filter 12 and is not supplied to the dispenser 22 and the ice-making unit 24.
On the other hand, when at least one of the dispenser switch 22a and the ice-making unit switch 24a is ON because water supply to at least one of the dispenser 22 and the ice-making unit 24 is needed, the first and second valves 32 and 34 are opened (STEP 115), so that water is supplied to the dispenser switch 22 and the ice-making unit 24.
The conventional method for controlling the purified water passage of the refrigerator constructed above has the following defects.
As known from the flowchart of FIG. 3, the opening and closing of the first valve 32 depends upon whether the refrigerator compartment door 16 is opened or not. That is, the first valve 32 is closed when the refrigerator compartment door 16 is opened, while the first valve 32 is opened when the refrigerator compartment door 16 is closed. Therefore, regardless of whether the second valve 34 is opened or not, or when water supply to the refrigerator is not needed, the first valve 32 is opened, so that water is continuously supplied to the filter 12 that is connected to the first valve 32. In such a case, since water is continuously supplied while water that has passed through the filter 12 is intercepted by the second valve 34, high water pressure is exerted on the filter 12. Since the filter 12 is mostly made of a minute material that is weak and subject to impact damage, such high water pressure may cause the filter 12 to be damaged.
Additionally, since water is continuously supplied to the filter 12, the amount of purified water is increased, and so the amount of impurities that are accumulated in the filter 12 is increased, also. Consequently, since the filter 12 is made of a weak material, the filter 12 is damaged by solid materials, thereby reducing the life span of the filter 12.
Further, whenever the freezer compartment door 26 is opened, the second valve 34 is closed unconditionally regardless of the ON/OFF of the dispenser switch 22a and the ice-making unit switch 24a. Therefore, it is impossible for a user to control the amount of supplied water after opening the freezer compartment door 26 and inspecting the amount of water that is being supplied to the ice-making unit 24.